Tuesday, 30 December 2014

Apple I replica computer build

My wife kindly purchased me a replica Apple I kit as a Christmas present, (the kind of present where I buy it and she pays me and wraps it up. lol!) The Apple I was the first computer designed and engineered by Steve Wozniak &  Steve Jobs. 

The kit is a replica made by Briel Computers. Inside the package was the following items: Blank PCB, Components & a CD containing build instructions, software and some original Apple I info.

Contents of the Apple I replica kit.
After a quick read of the build guide, I installed the components in what I deemed the best order.

Passive components, Power switch, Crystal USB->Serial headers installed.
All IC sockets, PS2 and Video Phono connectors installed. 
IC's and USB to Serial adapter installed.
So that was all the components installed, I double checked that everything was installed the correct way around. The first check was the 3.3V from the USB adapter, this is used so you can a) power the computer and b) connect a terminal program from a computer to send files and type code. There is an onboard PS2 connector to plug a keyboard in directly or even an ASCII keyboard connector which the Apple II used (I think).

So the 3.3V was good, next up was the 5V line which powered all the IC's. Again this was good so I hooked up the monitor.

1st power up, the screen is full of garbage.. this is what's expected. Yes!

After a quick press of the 'clear' button followed by the 'reset' button I'm staring at and "@" sign, this is the Apple I prompt, you are now in Woz Monitor mode, here you can set and view memory locations and program directly to the 6502 processor. The ROM that comes with this Replica has Apple Basic installed, back in the day you would have to build a Tape interface and load it into RAM from Cassette. To get into basic, you type E000R and hit return. There's also an assembler called Krusader built into the ROM, this is a assembly language dev tool for the Replica I which can be run from location F000R. This is what I'm going to be looking into once I've finished playing with some of the existing software releases for the Apple I.

A very basic Basic program!

I'll post some more updates, if/when I make any progress with anything that may seem remotely interesting.

Regards, Smart.

Saturday, 15 November 2014

Atari Jet Fighter. What's the score?

So another week goes by and my Jet Fighter board has another failure, these 40 year old 74 series logic seem to be dropping on a regular basis from being powered on for a few hours here and there...

This this when I started a game, the scores didn't reset to '0' for either player, when I scored some 'hits' on the other Jet the score moved in an odd sequence something along the lines of 2,3,2,6,4,11.

Out comes the operation manual and my printed schematics. The scores are initially generated by two identical circuits comprising a 7493 binary counter, Pins two and Three which are linked to the 'START' signal are used to reset the counter to zero when the game starts. Pin 14 is the counter input which is pulsed when either Jet is 'Hit'. The output pins hen count upwards to a maximum of 15 and pass on to some more circuitry.

Jet Fighter Score Counters
After playing a few games I noted the following... the score was being reset every time a game was started, just not to zero, and it was actually counting, just not in a sequential order, I made the assumption that these two counters would not be the issue as having two different IC's fail at the same time was improbable, If one of these had failed it would seem more likely that one of the scores would stop working and not both at the same time.

The next part of the circuitry that relates to the scores is shown below:

Jet Fighter Score selecting

The 74157 at location A5 receives the signals from the two 7493 counters. I used my logic probe to test the pins of this IC. Pin 1 was pulsing away as expected and the input pins were all the in the same logic state as the output pins from the 7493 counters. There are  four output pins used which feed into a Prom which selects the Score number data, by my testing, pin 12 which is output 4Y on the datasheet was stuck high all the time. Quickly piggybacking a new 74157 cured the scoring, but did seem to have a side effect of resetting the game a short while after stating a new game. Anyway once socketed, I put in a new 74157 and we're back to fully working again. My IC tester confirmed that output 4 of the IC was faulty.

Friday, 31 October 2014

Missile Command PCB fix

Board location E5 - 74160 dead output at pin 12 and other outputs suspect.

Confirmed as faulty in IC tester.
Fixed! :)

Saturday, 25 October 2014

Arcade Garage 1.0

Well after close to four years, all the cabs I own are (touch wood!) working, Well I need a new starter for my Tempest Fluorescent light, but thought I best capture them while they all do work. My current line up consists of:

Fire Truck, Jet Fighter, Electrocoin Midi with a dual JAMMA adapter playing Pac-Land & Wonder Boy, Tempest Cabaret, Centipede Cabaret, Hang-On and Pole Position.

On the way to getting my current lineup I’ve also owned the following cabs: Lethal Enforcers, Cruis’n World, Missile Command Cabaret, Asteroids Cabaret, a Popeye Pachislo & 2 JAMMA cabs.

Photos below and a video, sorry for the lack of commentary but I’ve got a stinking cold at the mo and the vocals don’t sound too good.

ATARI Hot Wheels!

Monday, 13 October 2014

Tempest. Board repair.

This board failed on me back in March, and I briefly looked at it but didn't really have the enthusiasm to fix it at the time, fast forward six months and here we go again...

So upon re-testing the boards, the X axis output had stopped working, this was caused by a failed TL082 at location D/E12 on the main AVG board, pin 7 wasn't outputting anything, I fitted a new socket and replacement IC and had a stable output again, back to where I was six months ago.

Last week I got stuck into this fault again, (Crazy vectors and Showing Mathbox error in test mode) I have spent a good few hours probing with a scope and logic probe to try and track down where the issue was, I got the schematics printed onto A1 paper at work, I even de-soldered all the proms from another Tempest AUX board to double check my proms had verified correctly, which they had.

Now, convinced that it wasn't a Prom/Bitslice/Socket or Interlink cable, I honed in on the remaining IC's in the Mathbox area. E4 a 7408 (quad 2-Input AND gate) got my attention, now I'm not really proficient enough in fixing boards to understand what was wrong but pin 6 which drives the clock input of B1 (374) didn't look pulse correctly on my logic probe, the frequency of the pulsing was all over the place and the HI/LOW LED's were going 'mental' in an odd way. I tried piggybacking a known good chip onto the 7408 to no avail, not deterred I de-soldered it and put a socket on the board. I then tested the IC in my Programmer which also tests 74 series logic, and sure enough one of the gates reported faulty. I put a new 7408 in and BOOM! The game is working again!

I have ordered new TL082's, MC1495's, trim pots for X/Y size/position adjustments and will fit these when the arrive to hopefully improve the reliability of this board, but for now I think I'm due a few credits. :)

Monday, 11 August 2014

New kids in the arcades....Animal Kaiser

So I just got back from a family in North Wales, I visited a few arcades and found them full of redemption machines, pushers and it has to be said a good stash of new sit down drivers and an Afterburner Climax cab. 

I never spotted a 'classic' machine on my travels, but I did stumble on a machine that was new to me; Animal Kaiser. At first from a distance I thought it was a new Sega Dino/Mushi king type cab upon close inspection it is a Bandai Namco cab. The game in a basic form is player one vs computer or player one vs. player two. You are an animal and you battle against your opponent. You only have two buttons, one chooses your attack and the other chooses the attack strength. Simple enough but, there is added excitement that after each game you get a game card which can be used in you next game. There are three types of card: 1) A red 'Animal' card, If you have one of these you can play with that animal in your next game. 2) a Green 'Strong' card that increases the power of you attacks and finally, 3) a Blue 'Miracle' card which acts as you special move.

When you start a game, you scan one of each card if you have them and that combines your strength and health and special attack. The games consists of three rounds (If you last that long) fighting a different animal each time with the big boss in round three. The game is like a skill stop selection, your first button press chooses your attack type which is dependent on your cards, and next button is the power of the attack, the game then takes over and shows you being attacked or you attacking the other player depending on who had the best attack. The idea is to knock their health down and wipe them out. Whether you win or loose, you get a new game card at the end of the game. As the name goes all the cards are based on different animals and in true collecting style some seem to be plentiful and others can be Gold/Silver & Bronze 'Rare' cards and one card is labelled as 'Ultra Rare' which is the character with the most strength.

I was amazed in the evening that these machines were packed with kids wanting to play all night long, at one pound per play these machines would have been making the operators a very good return. Not just that but there was a real buzz around the game and who had which card, a classic moment for me was when a small girl came up with her dad, he got some game cards out of his wallet and as she scanned them there were real gasps and cheers from everyone as she scanned the Ultra Rare 'Seigfried' card, this will be an awesome moment in my arcade memories as it was great to have my kids really getting a buzzing arcade experience. Lots of very jealous kids standing by in anticipation watching her game! We all had smiles watching, but she didn't make it though all three rounds even with one of the best card.

Between myself and my two kids we spent about £50 on the game over seven night, we got a few of the rare cards and the kids now want me to get a certain machine for the home arcade. lol. 

From researching since I've been back these machines have been around a fair while with these cabs having 2007/8 copyrights over them. This game was labelled revision four which is new in the UK, but there seem to be at least another four versions that have been released worldwide to date. See below for a few photos and a video of Son number one playing. Each game lasts around five minutes which in today's arcade, combined with the fact you get a card is pretty good value entertainment in my opinion.

After watching the games being played for a few days one finally ran out of game cards which needed an Op to open the cab up and put in some new cards, I took a few blurry photos as you can see below. There were 600 cards in the box and they were labelled as A,B,C & D. I couldn't tell if they went into different compartments and wonder if certain packs contained the Animal/Strong/Miracle cards etc.

Game cards in the box above, and the (blurry) service menu in the photo below.

Our card collection, including a Gold Rare and some Bronze Rare's.

If you want to find out where you can have you wallet emptied there is a map on the Facebook page that shows current game locations in the UK.

Thanks for reading, Mart.

Pole Position. Post race analysis

So the cab is now as complete as I'm going to make it. If I had more space I would do some cab woodworking to fix the broken corner then finish off with new T-moulding, but for now this is it.

A can of black satin spray was used to cover the new section of MDF at the bottom of the cab along with the recently made back door, the finished result can be seen below.

Another item on my list of thing to do was to make a cardboard monitor surround which site in between the front glass and monitor, I had no original surround for this so I made so I slowly measured and cut the card, the final result came out OK, not perfect but better than without one.

I finally got round to spraying the coin doors and fitting some new reject labels. I took three attempts at spraying the doors, mainly due to the fact I didn't sand and clean them well enough to begin with!

To finish thing off on the cab I finally applied the steering wheel sticker I bought a while back from arcadefixit.com

In true Pole Position style the game board has gone belly up just as I finally get things finished! After having a few games recently the cab decided that it wouldn't coin-up or go into test mode even though attract mode was still happily playing. Upon re-powering the cab I am now greeted with a blue screen full of zero's :(

*Update1* Mark at Retroclinic fixed the board set for me, I lasted a few weeks before failing again.

*Update2* I am now going to wait for Adam Courchesne to finish his Pole Position clone board before dropping any more money into this cab/

Tuesday, 1 July 2014

Atari Jet Fighter. PCB Repair Part 2...

Well after have a fair amount of play recently and being switched on for 10+ hours, Jet Fighter developed a fault when switched on a few days ago...

In attract mode the Black Jet was erratically flying backwards, not something I'd seen before with this board. When you started a game the Black Jet carried on flying backwards and the left/right rotate controls we not working for either Jet.

I started probing around the vertical and horizontal motion counters to see if I could track down the issue, there are four signal J1C0-J1C3 which are derived from a 64-bit RAM IC, probing these for the Black Jet circuit I found that they were all stick high and not pulsing as I would have expected.

This board is quite nice as the Black & White Jets have pretty much identical circuitry so it was easy to compare one with the other.

Checking out the other pins on the RAM, I found that the W/E pin was being held high, I traced this back to an LS7432 (2-Input OR gate) and confirmed that the output was stuck high (confirmed against the White Jet circuitry). I cut the output pin on the 7432 and was still stuck high and not pulsing away. Once swapped out with a replacement, The game is fully working again.

Schematics showing the area of the fault this time.

Saturday, 17 May 2014

Atari Jet Fighter. PCB Repair.

Back in March I fired up my new cab and was pretty happy with the results, The game powered up and seemed to work, with exception of what I took as a graphic fault seen below where the Jets were displayed multiple times vertically down the screen. 

Original testing in March. 
I decided I was going to spend some time to look at this board this week just gone. My initial diagnosis above was not quite correct... Looking closer at what was on the screen the 'Jet' graphic was not complete and had bits missing especially noticeable in the white Jet. Also it was not possible to score points, I thought it may be due to the fact so many Jets were on screen at the same time. So I was looking at multiple faults already, and as (bad) luck would have it, after having the board on soak for a few hours I looked at the screen to check the game was still running and all I could see was a black screen! A few expletive's came out of my mouth and then I re-powered the cab, the image below is what I now had to work with...

The black 'Jet' and 'Score' were missing and instead of having a solid light background colour there we now horizontal bands in alternating colour going down the screen. (difficult to see in the photo below, but move visible in the photos further down.)

The fault log begins with this screen.
I have a copy of the Operation & Maintenance manual and it has some great description of what signals control certain aspects of the game, this certainly aided my fault finding, I also printed some A3 schematics that I could mark up in pencil and highlighter pens.

Initially I did go round the houses trying to work out where in the circuit the faults were, but after reading the manual a few times and following the signals in the schematics I got hot on the trail of issues, cutting to the chase, the faults were as follows.

IC location F3 a 74LS10 (3 input NAND gate) now had no output from pin 12. This provided the Jet/Score and Shell for black Jet.

Black Jet & Score back, but Jet video is inverted.

So with video back, I played a few games and noted that the score wouldn't increase when the Jets were hit with shells and the fact that no explosion registered to say the Jet had been hit. As it turns out another 74LS10 this time at location E1 had no Output on pins 6 & 8, these are the two trigger signals for Jet 1 & 2 respectively that further down the circuit chain pulse a 'BLO UP 1/2' signal which is used for detection of a hit. With this IC changed the score now worked and Jet explosions happened when hit by a shell.
Scores now working
The White Jet graphic was slightly corrupt not correctly displaying properly, The data for plane comes from ROMS at J5 & K6 (2K each). This data is shared between the two planes, so as the black Jet looked fine (although inverted) I was pretty sure the ROMs were OK. The ROM data is fed into a pair of Parallel to serial converters. For the white Jet they are at locations J4 & K4. Pin 7 of K4 provides the serial data through a few more IC's before becoming the Jet 2 video signal. The IC clearly was outputting something as you could see the image on screen, but my Logic probe was saying that pin 7 had no signal (High/Low or pulsing) Pin 9 is the inverted state id pin 7 and although not used in the circuit appeared dead too. I compared this to the Logic to the Black Jet and those same pins were pulsing along nicely. Time to swap K4, once replaced the Jet graphic was spot on and working.

I needed to get to the bottom of the 'multiple Jets on screen' fault that this board has had since I first turned it on. I'll put finding this fault down to mild guess work and lots of general probing around. I had the opinion that the issue was in the Vertical motion counter section of the circuit. Seeing as the fault was on both Jets and that each Jet had its own counter I had a hunch that these weren't directly the fault. The output from the counter for both Jets was fed into a 74LS74 flip flop IC. Pins 5 & 9 are the output pins which are mixed with the Horizontal blanking and Horizontal Jet position. They were stuck low. I cut one of the pins in circuit to confirm nothing else was pulling the pin low and it stayed low. Time to replace it...
Wohoo! Fixed as shown below, just the inverted black 'Jet' video and the background bars remaining.

Only one black Jet (Video inverted) and one white Jet.
More general probing around the final stages of video signals before they are joined in a resistor network found me this fault, IC at E4 an 74LS08 pin 6 provides the final video data for the White Jet. (Jet video and H/V blank info) As with the earlier fault the output was working but using a logic probe gave odd results, I did 'piggyback' an IC on top of the one in circuit and the background issue was gone, so I replaced the IC and that left the inverted video fault...

I remembered reading in the manual that when a Jet was hit by a shell the Jet's video was briefly inverted, to me it seemed this was happening constantly. The 'BLO UP' signal comes out or a 2 input gate at position K8, the logic probe was telling me this signal was constantly low, I monitored this in a game and made a white shell hit the black Jet, the output on the gate stayed low. Next up I cut this pin and re-powered the game. The Black Jets video image was now the correct was round, using the White Jet I fired a shell at the Black Jet, the game functioned as expected but without the brief inversion of video (that pin now wasn't connected!) So I replaced the IC and for now the game is fixed and fully working.

I've really enjoyed getting these faults fixed and think I've learnt a fair bit these last few evenings. Now its time to sort the cabinet out.

Cheers, Mart.
Background banding issue fixed, inverted Black Jet video fixed. Game...Fixed!

Wednesday, 7 May 2014

Atari Fire Truck. Board repair's...

If you were lucky enough to make it down to the South Coast Slam a few weekends back you might had seem and had a play on my FT cab. Unfortunately when I fired the cab up on the Saturday morning of the show, a graphic fault had developed on the Truck part of the vehicle. A quick re-seat of all socketed IC's didn't help the situation and the show went on and Fire Truck had a graphic fault as shown below. (Horizontal black lines running through what should have been the truck.)

Lines running through the truck graphics.

So it's time to get the schematics out and fix the issue, but first let me step back to the original fault when I turned the cab on after firing it up for the first time... See the image below, the game was not playable, the background was scrolling madly and a constant audio tone was coming out of the speakers.

Original board fault from September 2013

I sent the board to Andrew Welburn (P-Man) who fixed the game and sent through the following diagnosis along with the fully working board.

 > Your pcb is now fixed... brief fix summary : Address buffer at 1A had a couple of stuck 
 > bits and was replaced.. the cpu was dead as a doornail and was replaced, the zero page 
 > ram @ N2 was bad so it was replaced along with a socket install too. There was also a 
 > loose patch wire on H5 the graphics ram buffer that was rectified.
So where did I start with the current issue; Reading the Operation & Service manual confirmed that the tail cab data is stored in two ROMS at positions J5 & L5. These can be read as 2716 ROMS and in my programmer the checksums they gave matched the checksum I generated looking at the MAME rom file in a Hex Editior so these weren't the issue, and I must say I had a good look for dry solder joints before looking into component failure, my initial assumption was that the road journey to the show had caused some of the 35yr old solder to fail...

Fire Trucks Tail circuitry
So testing with my logic probe I confirmed the Address and Data lines were happily pulsing away, the data lines from the two ROMs pass through an LS273 at position M5, again the data was coming out of this pulsing away looking like what I think is OK. I did note that If I shorted and Input pin to Output pin (i.e. 2&3 or 4&5) It would create a similar fault to what I was already there but in a different position on the graphic. Next in line to check was an LS151 at M6 this is where all the ROM data is turned into a single output called TAILVIDEO. The select lines on this chip were pulsing away and none of the data inputs seemed bad so I was a bit stuck... 

Hoping for the day that I find a leg on a chip that is dead, stuck low or high, I decided to order an LS273 and an LS151 and try piggybacking them to see if the problem is fixed, first up I piggybacked the LS273 at M5 and it made no change to the fault. BUT I had more luck with the LS151 at M6. Boom upon piggybacking this chip the video fault had gone. YES! I removed the faulty chip, put in a new socket, inserted the chip and the fault was gone. I suspect that one of the Data bits of the LS151 was internally shorted.

It would have been nice to find the exact fault, but I'm happy it only took a few hours in total to get the cab running 100% again. Until the next time...

Fixed! :o)

Wednesday, 30 April 2014

New Cab. Midway Cruis'n World.

I had a new cab delivered yesterday for the UKVAC raid that was in Exeter in March. This is the photo of the cab at the Op's and It was unknown whether it would work or not. Most other cabs were working so I was pretty hopeful.
Cab at the Op's.
After having the cab delivered, I proceeded to take all the usual steps I do with a new cab. Look for any loose screws or washers that would short out PSU's etc, unplug the monitor and  unplug the game board. Once that was done I turned the cab on and check the PSU and monitor voltages. Every thing checked out out mains voltage in 110V on the Switcher and 240V on the monitor. The PSU has +5,+12 & -5Volt all sitting nicely.

It was also nice to bee greeted to some paperwork and a service manual in the back of the cab.

Paperwork in the back of the cab.

Next up was plugging the monitor power back in, I was expecting to this not to work as I discovered this sign attached to the monitor board.

Dead or Alive?
Expecting sparks to start flying or smoke I cautiously re-powered the cab and fortunately the monitor seemed to power up ok, I had neck glow and some light on the tube. Fingers crossed this was actually working.

Next up was plugging the game boar back in... I turned the cab on and shat myself as it gave a few loud audio beeps which made me jump! After 30 seconds or so I went round the front of the cab to see this...

Its Alive!
Holey Moley the game seems to work! I coined up and off I went of a world tour. The coin mech. even works fine. I adjusted the volume to a more sensible level for home use and wow that's it, a working cab. a few more photos of the cabs insides:

The picture on the monitor need some adjustment as to focus looks soft and the image is washed out, but overall this seems to be a solid cab, The game is just a bit poor...

I'm also very interested to see the sticker below attached to the cab. Made by SEGA? Quite fitting as I do intend to turn this into a multi driver SEGA cab. Once my other project are up and running. Cheers to Oll for organising the raid!

Made by Sega? Interesting.

01/05/14 UPDATE

To slightly update this post, it seems this cab is the same what Sega used for Scud Race cabs as can be seen in the below photo. It has different pedals and dash but other than the it looks the same profile to me.
The manual for the Cruis'n cab also has the seat (shown on the Scud Race) as an option. I'd really like to find one of those as the pedals do sit quite high.